a. Field of the Invention
This invention relates to the protecting coatings or linings manufacturing industry, and more particularly relates to the industry specialized in the manufacture of water-proof protective coatings and weather-proof linings, useful for protecting several construction elements such as wood, bricks, cement, mortar, plaster, tiles, etc., but said elements also can be used with objects such as clay, paper, paperboard, etc., as ornamental and also protecting coverings.
B. Description of the Prior Art
It has been a main goal of the manufacturers of protecting products for those surfaces exposed to weather, the attainment of a type of coating which, further to provide a positive aesthetic appearance, is of great resistance and proved long-term life.
Some enamels or paints based on varnish have been known which are manufactured by mixing fine pigments and using said varnish as a carrier.
There is also a type of enamel capable of becoming dry quickly, and prepared with a varnish based on a synthetic resin. Said present enamels dry in a short time of from 2 to 4 hours, compared with the experience of some years ago, when said paints were made with oil or natural resin varnishes. There is also an enamel flat upon drying, and manufactured in the same way as those glossy enamels, with the only difference that a less fine pigment is employed, with a smaller proportion of varnish and a greater amount of volatil solvent as with said common enamel. However, this type of paints or flat coatings, due to their pleasant decorative effects, are employed indoors but they are wholly unsuitable for outdoors applications.
There are also a range of protecting coatings which are manufactured having in mind a concrete application thereof. Thus, several materials are known, particularly anticorrosive compounds and specially antiscale compounds, including the so-called marine-type varnishes, the practical application of which is positively outdoors.
However, it is broadly known by those skilled in the art that those usual varnishes, in a solvent-based solution, lack of yieldability, generally forming rigid films of a crystaline type, hard, brittle and without pores preventing thus the necessary gaseous interchange between atmosphere and the coated materials.
These characteristics result in the application of said type of varnishes to be negative due to the fact that, in a limited period of time fail upon exposition to humidity and sun radiation, and specially when applied on non-dimensionally stable substracts, such as wood.
In fact, wood is one of those materials which have presently greater application in the finishing of outdoors surfaces, due to its great aesthetic possibilities, but having, however, a main drawback consisting in the easy deterioration thereof due to eroding agents.
The glossy finishing of wood used in outdoor applications, is not the most suitable due to its few aesthetics and due to this, the skilled in the art have been seeking for a type of coating having a flat appearance for outdoor application.
As above stated, said flat varnish is not suitable for outdoors application, since for this effect substances producing flat effects should be incorporated therein, such as silicic acid or opaque charges, such as talcum, some carbonates, barium sulfate, diatomaceous earths, etc., thus adversedly affecting the life of said films since their humidity absorption is considerably increased, thus impairing the application thereof for outdoors finishings.
In the field of modern organic chemistry there is an active search for hydrophobic plastic aqueous dispersions which, in spite of its capacity of being diluted with water, when the film formed by said compounds is dry, becomes water-insoluble and posesses an extraordinary repelency thereto.
It also has been experimented with the so-called "large" varnishes or high-oil varnishes which due to their great content of this latter product, are more elastic than "short" or low-oil varnishes and, therefore, are more resistant to natural eroding agents.
However, there is no notice that a product based on a water-dilutable plastic varnish has been manufactured up to the date of this application, which becomes hydrophobic when dry and also a semi-glossy or flatproduct, with long-lasting characteristics to weather and having the possibility of being colored and grained upon passing a brush thereon from one end to the other, thus obtaining a wood-like effect.
This attainment is in contrast with the troublesome treatment of the prior art employed to improve the appearance of wood, color the same and produce a sort of graining of high-quality wood, such as, for instance, oak graining which required of a delicate labor by the painter with high specialization and, furthermore, of some danger.
The process used in the prior art consisted in scratching the wood with a special tool, followed by a dying with water anilines, which was protected with a couple of passes of gasoline-fused virgin wax.
The drawbacks of said complicated and time-consuming process are apparent: short life of the dying, since said anilines are not resistant to sun-light; sticky hand of said wax in warm temperatures; loosening thereof due to the action of water; damage of the gloss in short time and great inflamation danger by said wax-gasoline mixture. A finishing hand of varnish based on a solvent did not improve substantially the results.